The present disclosure relates to a power supply system and a power source apparatus.
Recently, research and development on the use of renewable energy have been popular in a bid to escape from the dependence on fossil fuel. As power generation which uses renewable energy, photovoltaic power generation, wind power generation, fuel cells, biomass power generation, wave power generation, and the like have been developed. When renewable energy is used, there are problems in that the amount of power generation varies according to natural conditions, and that excesses and deficiencies occur in the amount of power consumption. For example, although the amount of domestic power consumption is large at a specific time slot of a day, it is not limited that the time slot is coincide with a time slot that the amount of power generation is large.
In order to solve this problem, it is conceivable that a storage battery system be introduced to each house, output of photovoltaic power generation or the like is once accumulated in the storage battery system, and the output of the storage battery system is used according to consumption. In detail, the output of the storage battery system is caused to flow into a system at a time slot that is peak of the power consumption such that power is flatten out, a time shift is performed in which power is stored at a cheap time slot and discharged or consumed at an expensive time slot, or redundant power, which is generated using a power generating device, such as solar cells or the like, is stored in the storage battery system.
A system, which integrates power generation, power transformation, power transmission, and power distribution in order to supply power to the electric power receiving facilities of a customer, is called a power system (or a system). The electrical power that flows from the side of the customer into the power system is called “reverse power flow”, and the flow from the side of the customer into the power system is called “regeneration”. For example, power generated using a photovoltaic power generation system is supplied to an electrical power company. In this case, a power conditioner is arranged between the photovoltaic power generation system and the power system. The power conditioner converts the unstable Direct Current (DC) output voltage of the solar cells into a stable DC voltage, and further converts the DC voltage into an Alternating Current (AC) voltage. The power conditioner tracks the variation in power which is generated using the solar cells, and usually performs Maximum Power Point Tracking (MPPT) control.
In a power system in which both the solar cells and the storage battery system are used, the storage battery system is connected to the power conditioner. In such a configuration, the entire DC power of the storage battery system is converted into AC power using the power conditioner, and the resulting AC power is output.
A power conditioner in the related art causes interconnection to be released at a time point that an output voltage is a value which is not included in a prescribed range, that is, when feeding abnormalities occur. PTL 1 discloses a technology that prevents the interconnection from being frequently released. That is, a voltage (output voltage) at an interconnection connection point is observed and, when the output voltage approaches an upper limit voltage, setting is made such that the operating point of output current moves away from a maximum power point.